1. Field of the Invention
The present invention relates to an ultrasonic oscillator which drives an ultrasonic oscillating element serving as a load.
2. Description of the Prior Art
Cleaning or machining devices using ultrasonic wave have been put into practice and it has been recently proposed to use ultrasonic energy to facilitate atomization of fuel to be fed to an internal combustion engine of an automobile. As an example of an ultrasonic oscillator for generating ultrasonic energy, an arrangement shown in FIG. 1 is known in the art in which an oscillating element (ultrasonic oscillating element) 10 is connected across a base and a collector of a transistor 70 and a D.C. power source, such as a storage battery 1, is connected across terminals 3 and 4. With such an arrangement, when a current flows through the oscillating element 10 in the direction of an arrow a, an oscillation signal in accordance with an inherent oscillation frequency of the oscillating element 10 is generated. While it is possible to drive a load connected across the terminals 8 and 9, it is not possible to cause the oscillating element to generate a high ultrasonic energy because the oscillating element 10 cannot be supplied with high power. While a high voltage D.C. power source may be used in order to enable the oscillating element 10 itself to generate increased ultrasonic energy, it is a usual practice to use the storage battery 1 as a D.C. power source when an ultrasonic oscillator is mounted on an automobile. In an automobile, the vehicle body is used as a ground to which a terminal of the storage battery 1 is connected. Hence, if the oscillating element 10 is mounted on the vehicle body, and if a high voltage power line of the oscillating element 10 is brought into contact with the vehicle body or other electrical parts during maintenance and inspection operation, the electrical parts, or in certain cases the storage battery 1, are damaged and there also exists a risk that an operator may suffer a shock by touching the lead wire.